Spatial Data Analysis

Evgeny Noi

August 26, 2021

Possibly a first use case of spatial analysis

Dr John Snow and Cholera Outbreak

One of the first examples of spatial analysis is from epidemiology. Dr John Snow investigated the cholera outbreak in 1854 in London. He postulated that cholera was transmitted through drinking water and not air. He noticed that the outbreak was centered on Broad Street public drinking pump.

Repeating the first spatial analysis with current tools

There are many more projects…

Stages in Spatial Data Analysis

1. Map the variable you are researching

  • choropleth map
  • flow map
  • cartogram
  • dot density map
  • isoline map
  • …

  • Which areas (counties) have the highest mortality?
    • Why is Chicago significant and Minneapolis is not?
    • What happens in Montana?
    • What happens along the coast?

Analyzing attribute information

Remember normal distributions?

Histograms

Scatter plot

Is there a correlation? (fit the line)

Examples of Spatial Operations

North Carolina Data

## Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1

Reproject

Calculate distance

Distance Matrix

## Units: [m]
##           [,1]     [,2]      [,3]     [,4]
## [1,]      0.00 312184.9 128341.85 475623.3
## [2,] 440561.15 114939.7 590434.80      0.0
## [3,]  18944.03 352719.1  78756.89 517527.8

Overlay

Overlay Analysis

Overlaying in NC

##       [,1]  [,2]  [,3]  [,4]
## [1,]  TRUE  TRUE FALSE FALSE
## [2,]  TRUE  TRUE FALSE FALSE
## [3,] FALSE FALSE FALSE FALSE
## [4,] FALSE FALSE FALSE FALSE

Choropleth Map of County Areas

Choropleth Map of Births in North Carolina

More beautiful and custom maps

Centroids

Centroids + Proportional Symbols

Centroids + Proportional Symbols (Size) + Hue

Major US cities

Count cities in each county

  • Cities are points, counties are polygons
  • aasd